Organic light-emitting diodes (OLEDs) have been widely applied due to their advantages such as good self-illumination property, excellent contrast, quick response and flexible display.
There are following several ways for OLEDs to achieve full-color display: a: directly emit light by RGB organic light-emitting materials; b: white organic light-emitting device (WOLED) with a color filter; and c: light-to-color conversion with a blue light-emitting layer and a light-to-color conversion layer.
At present, the design of color filter in OLEDs needs to refer to the design of color filter in liquid crystal displays (LCD). In LCDs, the use of the color filter is necessary for achieving full-color display. A color filter substrate I generally comprises a black matrix (BM) 12, ala RGB color resist 13, a protective layer 14, and a plurality of photo spacers (PS) 15. The specific structure is shown in FIG. 1.
In an existing OLED structure, the photo spacers 15 are located above the protective layer 14. This may increase the distance between the WOLED and the color filter substrate 1, resulting in the mixture of colors. Furthermore, the photo spacers 15 are generally made from organic photoresists, which are pale yellow in color, and have certain light transmittance.